High AMP Transformerless Power Supply Circuit
Learn to build a High AMP Transformerless Power Supply Circuit with wiring diagram, components, working principle, step-by-step DIY instructions, and safety tip...
What is a High AMP Transformerless Power Supply Circuit?
High AMP Transformerless Power Supply. A capacitive dropper is used to drop the voltage on the AC mains and rectify it to DC. This circuit is small, light, and has a low cost, unlike the transformer-based supply used. It is able to provide a relatively high current to certain low-voltage applications, although this needs careful design and caution, as it is not galvanically isolated from the mains.
High AMP transformerless PSU
High AMP Transformerless Power Supply Circuit is a small electronic circuit that steps AC mains power into a regulated DC output, without any large transformer to do so. It aims at supplying high current (high AMP) loads safely with capacitive voltage drop and rectification methods.
The guide describes how to make a high-AMP power supply with no transformer, its parts, how it works, a wiring diagram, and DIY instructions on making it. These circuits are typically used by hobbyists and electronic hobbyists who do not need to use the massive transformers and just need a simple, low-cost DC power supply, especially when powering LEDs, motors, and other electronics. Safety precautions, applications, and problem-solving tips have also been discussed in this article to achieve reliable and safe operation.
Components Required for the Circuit
- High-voltage non-polarized capacitor (X2 rated, e.g., 0.33µF/400V AC)
- Bridge rectifier (diodes 1N4007 or high-current rectifiers)
- Resistors (1kΩ – 10Ω for discharge and current limiting)
- Filter capacitor (470µF – 2200µF, rated 25V–50V DC)
- Load (LEDs, motors, or low-voltage electronics)
- Fuse (rated for desired output current)
- PCB or insulated enclosure
- Connecting wires and terminals
Working Principle of Transformerless Power Supply
Capacitive Dropping Technique
A high-voltage capacitor reduces the AC mains voltage based on its reactance. It limits current without dissipating significant heat.
Rectification and Filtering
AC voltage after the capacitor passes through a bridge rectifier. The filter capacitor smooths the DC output.
Current Limiting Considerations
A series resistor or fuse limits the surge current to protect the load. Capacitor voltage and current rating determine maximum safe output current.
High AMP Transformerless Power Supply Circuit Diagram
- Connect the X2 capacitor in series with the AC live line.
- Add a series resistor for inrush current limiting.
- Connect AC lines to a bridge rectifier (4 diodes).
- Connect the output capacitor across the rectified DC terminals.
- Connect fuse in series with load for safety.
- Connect load to DC output terminals.
Step-by-Step DIY Construction Guide
- Mount X2 capacitor on insulated PCB.
- Connect a series resistor for current limiting.
- Connect the AC mains to the bridge rectifier inputs.
- Connect the filter capacitor across the rectifier output.
- Install a fuse in series with the load.
- Test the circuit with a multimeter before connecting the load.
- Apply AC mains carefully and measure DC output.
- Ensure enclosure is insulated and safe for mains.
Applications of Transformerless Power Supply
- LED strip lighting
- Small DC motor operation
- Low-voltage electronics projects
- Battery charging circuits (with current limitation)
- Compact hobby electronics requiring DC power
Safety Precautions
- Do not touch the AC input or circuit while powered.
- Use X2-rated capacitor for mains AC.
- Enclose circuit in insulated, non-conductive housing.
- Use fuse and current-limiting resistors.
- Avoid connecting high-power or inductive loads.
- Test with a multimeter before connecting the load.
Troubleshooting Common Issues
No Output Voltage
- Check capacitor and bridge rectifier connections.
- Verify AC mains supply.
Overheating Components
- Verify current rating of capacitor, diodes, and resistors.
- Reduce load or increase series resistance.
Load Not Receiving Current
- Ensure fuse is intact.
- Check rectifier and capacitor for damage.
Frequently Asked Questions - High AMP Transformerless Power Supply Circuit:
What is a high AMP transformerless power supply?
A power supply circuit without a transformer that delivers high current DC using capacitive voltage drop and rectification.
Which capacitor is used?
X2-rated non-polarized capacitor, e.g., 0.33µF/400V AC.
Can it power LEDs?
Yes, it is suitable for LED strips or small DC loads.
How does it work?
Capacitor drops AC voltage, rectifier converts to DC, and filter capacitor smooths the output.
What safety precautions are needed?
Use X2 capacitor, fuse, insulated enclosure, and avoid touching AC input.
Can I use it for high-power motors?
No, transformerless PSU is for low-power DC loads only.
Do I need a fuse?
Yes, to prevent overcurrent and protect the circuit and load.
How do I adjust output current?
Change series resistor or capacitor rating to limit current safely.
Is isolation from mains available?
No, transformerless PSU is directly connected to AC mains, so caution is required.
Can beginners build it?
Yes, with proper understanding and safety measures, but mains voltage risk exists.
